WAR WITH IRAQ / AIR AND GROUND | MILITARY ANALYSIS

Quick Knockout Or Street Fight?

U.S.: The aim is to hasten Baghdad's fall by defeating Republican Guard units on the outskirts.

WASHINGTON — U.S. forces are poised to begin the battle for Baghdad by pounding Republican Guard troops on the southern perimeter of the Iraqi capital, hoping that with a crushing blow they can demoralize the remaining forces and avoid a bloody urban battle of attrition.

After a week of breakneck advance and skirmishing, about 75,000 U.S. troops are confronting about 35,000 Iraq soldiers arrayed in three Republican Guard divisions south of the city.

Yet tough terrain, new Iraqi tactics, restrictive American rules of combat and limited U.S. forces could make the fight longer and bloodier than U.S. commanders expected.

"It's going to be tough work, dangerous work -- we're going to take casualties," warned retired Army Gen. Barry McCaffrey, who commanded a division in the 1991 Persian Gulf War.

President Bush could face a momentous military and political decision: whether to move now and maintain momentum but risk heavy casualties, or await the arrival of the 4th Infantry Division, which could be weeks away.

Unless U.S. commanders decide to wait for reinforcements, the airstrikes already launched against the dug-in Iraqis could soon be supplemented with an artillery and rocket bombardment. Then, hundreds of U.S. tanks would open a full-scale ground assault, with the goal of destroying most of the Republican Guard's equipment before it could be withdrawn into the city, experts predict.

U.S. leaders are eager to avoid a fight in Baghdad for fear that it would cause huge casualties among troops and civilians, and widespread destruction.

The Republican Guard units are within 50 miles or so of Baghdad. They include the Medina Division north of Karbala and the Baghdad Division toward Al Kut. A few miles behind them, in a supporting role, is a third division.

Arrayed against the Iraqis are the U.S. 3rd Infantry Division, south of Karbala, and the 1st Marine Expeditionary Force, moving into position to the east, south of Al Kut. Other U.S. units, including troops of the 101st Airborne Division and a Marine brigade, bring the total force near Baghdad to about 75,000 troops, said Daniel Goure, a former Pentagon official now with the Lexington Institute research firm in Virginia.

U.S. forces in the war theater total about 250,000, and are growing by about 2,000 a day, according to Defense Secretary Donald H. Rumsfeld.

This week, the Republican Guard divisions were designated the top target of U.S. air attacks, displacing Iraqi leadership facilities in Baghdad. "We are shifting from one phase of an operation to another," Col. Gary Crowder, a senior planner with U.S. Air Combat Command, said in an interview.

In addition to the Medina Division, Air Force and Navy strike aircraft are attacking the Hammurabi Division, one of two Republican Guard units north of the city, officials said.

This suggests that the United States might drop paratroopers from the 101st Airborne Division into the north side of the city to begin an assault and close off access routes. The 101st Airborne alone has 72 Apache attack helicopters that could destroy large numbers of tanks and armored vehicles as the main body of the U.S. ground force was sweeping toward the city from the south, military strategists said.

Some U.S. officers in the field said they were eager to begin the attack. "We're going to take the full fight to him," Col. Ben Saylor, chief of staff for the 1st Marine Division, said in an interview. He said his division will take the middle part of the battlefield when U.S. ground forces begin their assault, with the 3rd Infantry to the west and other Marine units to the east.

The timing of the attack remained uncertain. Some Pentagon officials said U.S. forces may pause to let the air attack "soften up" Iraqi field forces, while U.S. ground forces resupply and consolidate at the front lines. "We've already taken a lot of ground, and we've done a lot of things with fewer forces than have been used before," one Pentagon official said. "I'd say it's a good time to breathe, rearm, refuel."

Some officials have also suggested that U.S. forces might want to take time to conduct reconnaissance on the Republican Guard units, which have been maneuvering rapidly in recent days as a sandstorm obscured their movements.

And it may take some time for warplanes to take out the Republican Guard forces, which are well-concealed.

In the 1991 war, allied air forces crushed Iraqi field equipment that had nowhere to hide in the featureless desert of southern Iraq and Kuwait.

This time, the Republican Guard has hidden tanks, armored personnel carriers and other equipment under trees and near mosques, schools and hospitals to protect them from U.S. forces that are reluctant to risk civilian casualties and infrastructure, military officials say.